Insulator for an open coil electric heating unit



FIG. 1 is a front elevational view of an insulator for an open coil electric heating unit, showing my new design;

FIG. 2 is a side elevational view thereof,

FIG. 3 is a front perspective view thereof, and

FIG. 4 is a rear perspective view thereof. 

The ornamental design for an insulator for an open coil electric heating unit, substantially as shown. 